Two former NHS employees, Alan Hush and Gavin Cox, were sentenced to eight years and six years respectively.
Oricom director, Adam Sharoudi, was jailed for eight years. Gavin Brown, also a director at the firm, was given a seven-year prison sentence.
This is a landmark case for NHS Scotland Counter Fraud Services (CFS) who led the investigation with support from Police Scotland and the NHS Counter Fraud Authority's Digital Forensic Unit.
Investigators collected over 4,000 items of evidence, including dozens of mobile phones and laptops. More than 250 witnesses were also interviewed during the investigation.
The case began with an enquiry over the theft of mobile telephones and bills for their use abroad.
Further investigations, led by CFS, identified that between 2010 and 2017, Hush and Cox accepted bribes, hospitality and cash incentives worth £100,000 in exchange for sensitive information that led to the awarding of contracts worth £6 million.
The contracts related to the supply, installation and maintenance of telecommunications and video conferencing throughout NHS Scotland.
The investigation identified that many of the incentives were later paid for by the NHS through false, inflated or duplicated invoices.
In 2015, Police Scotland and the NHS Counter Fraud Authority's Digital Forensic Unit (DFU) supported CFS in executing search warrants at NHS and Oricom premises, where digital and physical evidence was retrieved for examination.
The DFU created an on-site forensic image of the Oricom servers, and the remaining digital devices were taken to the DFU offices in Newcastle for analysis.
Tens of thousands of text messages and emails were reviewed. They uncovered deliberate acts to divert or manipulate NHS funds for personal gain at the expense of patient care and public trust.
Gordon Young, Head of NHS Scotland Counter Fraud Services at NHS National Services Scotland, said:
"This is a landmark conviction for fraud, bribery and corruption of individuals who sought to exploit the NHS for personal gain. This successful prosecution reaffirms NHS Scotland's commitment to safeguarding vital funds for patient care as intended by the taxpayer.
"These sentences send a strong and unequivocal message that fraud, bribery and corruption within the NHS will not be tolerated and we will act decisively against anyone who threatens its integrity.
"The prosecution's case was built on extensive evidence following the investigation, led by NHS Counter Fraud Services, which uncovered deliberate acts to divert or manipulate NHS funds for personal gain at the expense of patient care and public trust.
"Police Scotland and the NHSCFA's Digital Forensic Unit supported Counter Fraud Services in the investigation.
"We also work in partnership with all Health Boards across Scotland to protect NHS funds and resources from any form of financial crime. This partnership working was vital in securing this prosecution and I would like to thank the Health Boards involved in this protracted investigation for their unwavering commitment."
Chris Atkinson, Digital Forensic Lead at the NHSCFA, said:
"This case highlights the growing importance of digital forensic work in tackling NHS fraud and supporting prosecutions.
"The careful retrieval and analysis of electronic evidence by the NHSCFA's Digital Forensic Unit helped to build a clearer picture of how public funds were misused over a number of years.
"Whilst no single piece of evidence can tell the whole story, the digital trail proved vital in helping investigators understand the scale and nature of the wrongdoing.
"We're proud to have contributed to this successful outcome, working closely with NHS Counter Fraud Services Scotland and Police Scotland. Collaboration across the four nations remains key to protecting NHS resources and maintaining public trust."